Sunday, May 29, 2016

NEA2016 Panel on Preparing for New Reactor Development





This was a most interesting panel indeed, and panel chair and moderator Maria Korsnick of the Nuclear Energy Institute does a great job moderating the discussion (as well as making sure the audience applauded the panel even before the discussion begins, to recognize the eminence of the panelists individually and collectively, very appropriately in my opinion.) Below I excerpt some of more interesting comments made by the panelists at various points in the discussion.

Cynthia Pezze (Westinghouse Nuclear) : Last year we (Westinghouse Nuclear) decided to take a long look ahead, and we decided to focus on the Lead Fast Reactor (LFR). It has a number of advantages - containment at atmospheric pressure, a low coolant operating temperature relative to its boiling point, a compact nuclear island in most conceptual designs,  a core with high density which shields against gamma rays, a high burn-up ratio (increased fuel utilization) etc. Pezze wanted the industry as a whole to move the discourse beyond the safety issue and would like the industry to talk more about things like higher burnup and fuel utilization in the advanced nuclear designs.

Jacob DeWitte (Oklo): Oklo reactor is 2MW in power output; containerized design meant for off-grid or microgrid solutions... The paradigm (for building SMRs) is manufacturing and not construction. The perception that NRC does not have the resources to process a design certification for SMRs is not correct (based on Oklo's own experience). Mass manufacture drives costs down, which translates to lower electricity costs, since capital construction costs drive the price of electricity. But a comparison with the existing cost structure in off-grid is also instructive: the electricity costs in an off-grid location based on diesel generation are much more than in on-grid communities, so the adoption barrier is lower. On safety - physics-based safety should be the term in preference to inherent or passive safety.

Kuzynski (Southern Nuclear): Risk-informed regulation and performance-based (i.e. not prescriptive regulation) are both needed. This would change both the number and character of the regulations - he wanted to let the innovators figure out how to do it (i.e., satisfy a given regulatory requirement). NRC should enable this technology (advanced nuclear reactors) because it improves safety, without worrying about the semantics around whether enabling in this sense also amounts to promoting, which as a technology-neutral regulator it should not be doing. Further, he added that the SMRs and advanced nuclear designs should have no need for accident coverage based on Price-Anderson, as they would be inherently safe and would not lead to core melting in even the worst case scenarios.

Wednesday, May 25, 2016

Senate Hearing on Advanced Nuclear Technologies - 17 May 2016




I am one of those who do pay attention to the making of policy in legislative hearings, and my interest in energy, and nuclear energy policy in particular, is extremely high. While something is always learnt by listening or watching such hearings, this particular session of the US Senate Energy and Natural Resources subcommittee on Advanced Nuclear Technologies was extremely educational indeed. Apart from the details of reactor systems which actually emerged in the prepared testimony and subsequent questioning of the panelists by the Senators, the thorny issue of subsidies and implied subsidies to the nuclear, wind and fossil fuel sectors was openly and frankly discussed, and while that subject will not be much discussed in this blog post, which will restrict itself mainly to the details of some advanced reactors (details that, to the best of my knowledge, have not been in the public domain thus far), it must be noted that I found the open discussion of the subsidies issue - among and between the Senators and the panelists most enlightening indeed.

For someone like myself, who keeps a fairly close eye on developments on the Small and Modular Reactor (SMR) field, it was triply, if not quadruply surprizing to find out about Oklo, an SMR company that takes its name from the uranium mine in Gabon where a water-moderated nuclear reactor ran naturally for billions of years! I had never heard of it before I watched this hearing! Even now, the company has a particularly low profile so much so that the entire first page of Google hits on 'Oklo' refer to the Gabon uranium mine. [In what follows, 'Oklo' refers to the company, and not the mining site; 'Oklo reactor' refers to the reactor the company proposes to design, build and market.]

Oklo: Dr. Jacob Dewitte, CEO of Oklo, said that Oklo formally launched in 2013 though it had been operating for a few years earlier - he said that he saw the economic opportunity for an SMR company - in going small and being off-grid (one notes here that the 'SMR' category can span quite a range in reactor sizes and thermal/electric ratings - and the proposed Oklo reactor appears to be at the really small end of the size/power spectrum. One could even call it a 'micro' reactor, as indeed Committee Chair Senator Murkowski actually did. (Update: At the NEA2016 Panel on Preparing for New Reactor Development on May 24 2016, Dr DeWitte clarified that the Oklo reactor was 2MW). Furthermore, Oklo is focusing on the off-the-grid segment, while many others are specifically designed to be grid-connected). Dr Dewitte explained that Oklo has completed confirmatory verification and validation testing on full-scale heat transport – and hopes to do testing for transients soon. This is  similar to what NuScale did a few years ago. Here Dr. DeWitte explicitly acknowledged the role of NuScale in blazing a regulatory first of a kind path.


Another way of emphasizing the advantage that size confers on Oklo was noted by Dr DeWitte: ‘we’re so small that we can do everything (i.e. all the testing) at the exact scale’, while NuScale had to build smaller scale models for the thermalhydraulic testing, and then use similarity arguments and simulations to understand how the full-scale model might behave. Dr. DeWitte anticipates Oklo submitting a license application to the NRC in the 2018-2019 time frame; and envisions the first deployment of an Oklo reactor in the early 2020s.

While the Oklo reactor is designed to deal with spent fuel from the current  PWR reactor fleet – he anticipated that the initial fuel will be regular, normal enriched uranium – because Oklo does not want to add to the technological (his emphasis, to stress that it does not add to the safety risk) risk by using spent fuel at the initial stage. He clarified, upon questioning by Senator Heinrich (D – NM.) that the level of enrichment of the initial fuel for Oklo would be on the order of 15% – and further that it will be a relatively small amount of fuel, as the reactor itself is so small (even within the SMR category, and certainly in comparison with a 1GW class reactor) adding further that Oklo is definitely interested in opportunities to help with the plutonium disposition issue, and anticipates that in the future it would operate in a fuel cycle where it is able to fission all the actinides including plutonium by using as its fuel the spent fuel from the PWR fleet. (And here I must acknowledge how impressed I was to hear a technical question such as this from a Senator!)

At the very end of the hearing, Senator Murkowski, Chair, asked about the potential of Oklo as a ‘micro’ reactor in remote areas or islands like Guam or in locations like Bethel in her own state of Alaska, asking how Oklo could deploy at such places. Dr DeWitte said that it (Bethel, AK) was exactly the kind of market Oklo was targeting, and that the proposed Oklo reactor module would be buried 20 foot deep, but could also be 'mounded up' above ground. He further added that it is expected that the Oklo reactor would produce power for 12 years before refueling. Most interestingly (to me), Dr DeWitte explained that many SMR designs, and Oklo's specifically - also 'changes the paradigm' on load-following vs leading, and that Oklo can operate very easily at anywhere from 10% to 100% of rated power, just like gas power plants do. 

TerraPower: Dr. John Gilleland of TerraPower used the occasion to clarify the distinction between ‘spent fuel’ that Oklo plans to use, and ‘depleted uranium’ that TerraPower plans to use - depleted uranium is the uranium left behind at enrichment plants – never having been enriched or seen a reactor, while spent fuel is the formerly enriched fuel which has made its way through a reactor. Dr. Gilleland also clarified that the US State Department has negotiated an agreement with the concerned Chinese authority which allows TerraPower to freely exchange information with China on its Traveling Wave Reactor, the rationale being that, because (eventually) enrichment will not be needed for its fuel and reprocessing will never be needed, there would be no risk of proliferation of sensitive technologies via such exchange. TerraPower's goal, he added, was to come up with a reactor that could be universally and ethically exportable. He anticipated that construction on the first reactor would begin in 2018, and the first prototype would be in operation in 2025-26, and the first commercial units a few years after that. He emphasized that US national labs were playing an important role in materials development for TerraPower, which uses both a metal fuel (the depleted uranium) and a metal coolant (liquid sodium). 

Dr. Mark Peters, Director of the Idaho National Laboratory (INL) mentioned that the Advanced Test Reactor (ATR) at INL carries out a number of activities in support of the Navy's Reactor program – and has a planned operational timeline for the ATR that may have it working till 2050. the ATR will also serve as the main testbed for activities under GAIN (The Gateway for Accelerated Innovation in Nuclear). He clarified also that TransatomicPower (not represented on the testifying panel) proposes an MSR that would need access to the ATR through GAIN, and that, among all US National Labs, Oak Ridge has the strongest expertise on MSR reactors.

(The video embedded above was made available on youtube by Rod Adams (@atomicrod))